Improvement in the manufacture of white lead



R. ROWLAND.

Patented April 19, 1864.

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Bonner nownAn-inon NEW YORK, N,

c IMPROVEMENT IN THE MANUFACTURE OF WHITE LEAD,

Specification forming part of Letters Patent No. 412,407, datedApril.19, 1864.

To all whom it may concern Be it known that I, ROBERT ROWLAND, of thecity, county, and State of New York, have invented certain new anduseful Improvements in the Manufactureof White Lead; and I do herebydeclare that the following is a' full, clear, and exact description ofthe construction andoperation of the same, reference being had to theaccompanying drawings, in which-- i Figure 1 represents a perspectiveview of an apparatus which I use in my process. Fig. 2 represents alongitudinal vertical section through the same. Fig.3 represents avertical cross-section through the apparatus.

My invention consists in converting granulated lead into Whitelead bysubjecting it, while ina state of agitation within an air-tightcompartment or receptacle, to the action of oxygen, acetic acid, andcarbonic acid, thereby gaining great advantages, whichwill be set forthby the following description.

In the manufacture of white lead as heretofore practiced the lead, insheets or proportionate large pieces, is exposed in a state of rest tothe action of gases which convert it into white lead. It is placed upongrates or perforated bottoms within rooms or'boxes, and when handled bythe operatives they not only inhale the minute particles of white lead,but also some of the gases used in the manufacture, and those influencesoperate highly pernicious on their health. In that process the whitelead formed on the lead has to be washed off and the remaininguncorroded metallic lead has to be remelted if it is to be used again inthe manufacture of white lead. This entire manipulation is not only avery laborious one, taking up considerable time and labor, but itendangers the health of the operatives, and the remelting of the leadcauses such a loss in the quantity of the material that it constitutes alarge item in the manufacture of White lead. These difiiculties andlosses in time, labor, and material are obviated in my process. I usethe lead in a granulated state, to which it can be reduced while cold bya suitable machine or any other process. The granulated lead isintroduced into a revolving drum or barrel, which isclosed air-tight,and into which I introduce the gases necessary to the corrosion.

The following apparatus may be used in this process, and 1 will describeit, as it will fully illustrate my invention.

-I do not limit myself to an apparatus of any specific construction, asthe construction may be modified in many points.

A represents the frame of the machine,to which the journal-boxes Eare-secured.

This drum is composed iron end plates, F, which support the woodenparts, the entire interior being made of wood, so that no part of leador any gases used in the manufacture maycome in contact with I an ymetal parts of the apparatus. The sides of the drum may be made ofglass, to admit the l ght into the interior, it having been found thatlight has a very important action in the corrosion of the lead or thedrum may be made entirely of wood. The trunnions or journals 0 aresecured to the iron end plates, F, and

the wooden pipes G are set within the journals 0. They are provided withrims a, fitting within asuitable recess of the journals to prevent anylongitudinal motion of the pipesG, and they are connected with. pipes bc d, made of non-metallic substance, through which the gases necessaryfor the manufacture of white lead are'introduced into the apparatus. Thepipes G do not fit tightly within the journals 0, and when the latterrevolve with the drum the inner pipes, G, remain stationary. The latterextend sufficiently into the drum B so as to discharge the gases nearits center and to cause their general diffusion through the apparatus.

H represents perforated shelves or partitions within the drum, which areintended to agitate the granulated lead so as to thoroughly expose it tothe action of the gases.- Each shelf consists of two inclined planes,which converge toward the center, each preceding shelf dischargingthematerial onto the center of the succeeding one, whence by itsgravitation it rolls toward the ends of the inclines, again returns tothe center, and drops on the succeeding shelf.

The pipes b c at above described serve to introduce into the apparatusthree different gases, which I use in the manufacture of white lead,viz: acetic acid, carbonic acid, and oxygen or ozone. Each of the pipesis provided with a valve or stop-cock to regulate the quantity of gas tobe admitted, or to shut it off altogether. The action of oxygen ishighly energetic iii accelerating the. corrosion. of the lead incombination with acetic acid and carboniciacid, and for this purpose Iintroduce a separate jet of oxygen, and I thereby not only acceleratethe process, but I obtain a more perfec-t oxidation of the metal.

In the use of the granulated lead each grain presents alarge surface tothe action of the.

of a temperature of about 100 Fahrenheit,

and lead, either granulated or red need to a fine state, is introducedinto the apparatus. A

suitable quantity of granulated lead having been introduced into theapparatus, the action of .thegases and of the light accelerates thecorrosion. I Owing to the increased surface of the lead in itsgranulated state, and to the action of the oxygen, the metal isconverted into white lead. The slow rotation of the drum B continuallyexposes new surfaces of the metal to the action of the gases, detachesthe white lead formed on the surface of the lead grains therefrom, andthus a minute fresh metallic surface is continuously corroded until theentire metal within the drum is acted upon. Should, after the conversionof the metallic lead into carbonate of lead, the latter contain acetateof lead, the said acetate of lead can be converted into carbonate oflead by shutting ofi' the supply of acetic'acid, and the carbonic acidand oxygen will readily convert it into carbonate of lead, whichotherwise would erative.

have to'be separated and lost by washing, and I thus gain a highpercentage in the product.

This apparatus perfectly protects the operative from inhaling any of thegases used in the manufacture of the article or the dust arising fromthe white lead-influences which are highly pernicious on the health ofthe op- In removing the white lead from the drum,.it may be moistened toprevent any dust from arising. The material is entered in and dischargedfrom the apparatus through the door I. It will also be readilyunderstood that by this process I produce an article of excellentquality, as it is protected against all impurities, and the supply ofthe gases necessary to produce the very best article can be adjustedwith the greatest accuracy and no gases injurious to whitelead can'haveaccess thereto.

Having thus fully described the nature of my invention, what I claimherein as new, and desire to secure by Letters Patent, 'is-' 1. Themanner herein described of converting granulated lead into white lead bysubjecting it while in a state of agitation to the action of oxygen,acetic acid, and carbonic acid, substantially in the manner'and for thepurposes herein described.

2; Ind uctingthe gases used in the earbonization of lead into arevolving drum by means of separate pipes or tubes provided withstopcocks so that the supply of each of the gases can be regulatedindependently of the other, substantially in the manner and for thepurpose herein described.

' ROBERT ROWLAND. Witnesses:

J. ADELBERG,

R. W. RAYMOND.

